- Javascript is very liberal (very less error throwing)
- it is used to make webpages interactive.
- NodeJs In order to use javascript outside the browser
- Raplit Web application for writing Javascript and many other languages online
- var is defined globally and can be declared again and again.
- let is defined for or between the particular block only and is prefered, can't be redeclared(throws error).
- const neigther be redeclared nor their values can be changed
Primitive datatypes in js
- We have 7 primitive datatypes
- N Null (empty)
- N Number (33)
- S Symbol ("Anything")
- S String ("You are a sweet person")
- B Boolean (True/False)
- B BigInt (54449)
- U undefined (=0, intialized)
Objects or Non-Primitive data types
- Similar to dictionaries in pyhton.
- Multiple variables can declared in the object block
- Can look up variables using key
const item= {
"Gurdev":true,
"sharn":58,
"harsh":undefined,
"Taish":"Chhoti Bachi Ho Kya"
}
console.log(item)
- Arithmetic operators
- +,-,*,/,**(exponantial),++(increament),--.
- Comparison operators
- ==,!=,<,>,===(compare datatypes even),!==,?(condition? true : false)
- Logical operators
- for(intialize; condition; updation)
for (let a in object){
console.log(a) //prints keys of an object
}
- for of loop
-
for (let a of object){
console.log(a) //prints value of object
}
- do while loop(executes atleast once)
do{
statement
}
while(condition)
-
const name = (parameters) => {
statements
}
string Templates-Literals(string interpolation)
- Strings are immutable
-
let b1 = "harry"
let b2 = "garry"
let sentence = `${b1} is friend of ${b2}`
b1.toUpperCase()
b1.toLowerCase()
b1.slice(0,4)
b1.replace("har", "par")
- muteable, a type of object